Management of pterygium: our experience and a simplified treatment algorithm

Aim: To explore various approaches in the management of pterygium and to propose a simplified treatment algorithm for its surgical management. Methods: A retrospective analysis of 9219 eyes was done. Group I included patients with primary single-head pterygium, most undergoing pterygium excision with conjunctival autograft (CAG). CTG-P (Conjunctival tissue graft from pterygium), AMG (Amniotic membrane graft), and inferior CAG were done in the remaining patients in this group in which conventional conjunctival autograft was a relative contraindication. Group II included patients with primary double-head pterygium who underwent vertical/horizontal split CAG, with/without limbal orientation, Inferior + Superior CAG, CTG-P, and CAG + CTG-P. Group III included patients with recurrent single-head pterygium who underwent ER (Extended resection) + LCAG (Limbal conjunctival autograft), LCAG + MMC (Mitomycin-C), CAG + MMC (Mitomycin-C) and CAG. Group IV included patients with recurrent double-head pterygium who underwent split LCAG and CAG + SLET. Results: All the four groups reported a low incidence of pterygium recurrence. Recurrence was observed at a rate of 0.47%, 3.63%, 2.86%, and 7.69% in Group I, Group II, Group III and Group IV respectively. Discussion: We mainly aimed to get minimal recurrence and good cosmetic outcomes. In double-head pterygium, we could achieve good and comparable outcomes with horizontal or vertical split CAG, with or without maintaining limbal orientation. Similarly, Inferior + Superior CAG, CTG-P, CAG+CTG-P, and AMG also showed low recurrence rates. In recurrent pterygium, ER + LCAG/CAG, with/without adjuncts like MMC showed low recurrence rates. Thus, all of these methods were found to be viable options. The main strength of our study, compared to previous studies on pterygium was its large sample size and long duration of follow-up. Conclusion: All the methods we studied had a low recurrence rate. We have formulated a treatment algorithm for pterygium management based on our outcomes. Abbreviations: CAG = Conjunctival autograft, CTG-P = Conjunctival tissue graft from pterygium, ER = Extended resection, MMC = Mitomycin-C


Introduction
Pterygium is the development of a wing-shaped tissue encroachment over the cornea.Exposure to ultraviolet radiation is one of the major contributing factors.Despite its common nasal occurrence, doublehead pterygium is frequently seen in tropical countries [1].Elastotic degeneration of conjunctival collagen is the main histopathological feature [2].
A crucial aspect of pterygium treatment is to decrease the likelihood of recurrence.Factors like incomplete resection, bare sclera technique, and young age can contribute to pterygium recurrence.

Romanian Journal of Ophthalmology
Pterygium surgery has been performed for more than 3000 years since the era of Sushruta [3].Different surgical techniques have been explored, each presenting unique advantages and disadvantages.Conventional CAG (Conjunctival autograft) is widely regarded as the standard of care.The superior bulbar conjunctiva may not be accessible at times or provide adequate coverage for bare scleral defects.Hence, a range of techniques have been explored.
Our study details our approach to managing various forms of pterygium through some procedures.
We have developed a treatment algorithm based on our findings to guide the management of different pterygium types.

Materials and methods
The study encompassed pterygium excision procedures conducted on 9861 eyes between January 2005 and December 2020.Of these, 9219 eyes met the 12-month follow-up requirement and were included in the retrospective analysis.The duration of follow-up varied between 12 months to 15 years.In this study, the data was collected from the hospital's EMR (Electronic Medical Records).In total, 7663 patients underwent pterygium excision, among which 6107 underwent unilateral and 1556 underwent bilateral pterygium excision.7602 eyes underwent nasal pterygium excision, whereas 904 eyes underwent temporal pterygium excision.Regarding gender distribution, the study comprised 4201 males and 3462 females.The patients were classified into four groups based on the characteristics of their pterygium.
Group I included 8506 eyes with primary singlehead pterygium, Group II included 385 eyes with primary double-head pterygium, Group III included 315 eyes with recurrent single-head pterygium and Group IV included 13 eyes with recurrent doublehead pterygium.328 eyes had recurrent pterygium and 398 eyes had double head pterygium.Table 1 outlines the various surgical methods employed across the four groups.All surgeries were performed at a tertiary eye hospital in India's Southern part by a single experienced surgeon.Recurrent pterygium was classified by the degree of its involvement [6].Individuals with actual corneal recurrence were operated on.
The protocol for the study was consistent with the ethical standards of the Declaration of Helsinki.The study protocol adhered to the tenets of the Declaration of Helsinki and obtained clearance from the Institutional Ethics Committee.

Surgical procedure
In all the methods, the graft was fixed using fibrin glue, Tisseel (Baxter, Austria).
CAG -A superior or superior-temporal conjunctival graft was dissected.It was then used to cover the defect over the sclera.
CTG-P -The conjunctival layer from the pterygium was separated.It was then used to cover the defect created by removing the tissue beneath.
Inferior CAG -Graft tissue was harvested from the inferior conjunctiva.
ER (Extended resection) + LCAG (limbal conjunctival autograft) -The pterygium tissue was dissected extensively. 1 mm margin of conjunctival tissue and 0.5 mm margin of tenon was also removed.When harvesting the graft, a portion of the cornea was also included.Dissection of 100 microns thickness and 0.5 mm into the cornea was done.This graft, containing stem cells of the limbus, was placed on the defect over the sclera.
Horizontally split CAG -Graft tissue was harvested from the superior portion of the conjunctiva.This graft was then divided horizontally to obtain two parts.The split conjunctival autografts were placed over the defects over the sclera on the two sides (Fig. 1 A-C).
Vertically split CAG -Graft tissue was harvested from the superior portion of the conjunctiva.This graft was then divided vertically to obtain two parts.The split conjunctival autografts were placed over the defects, the sclera, on the two sides, either with or without limbal orientation (Fig. 1 D-I Inferior + Superior CAG -One graft was harvested from the superior conjunctiva and one from the inferior.These two separate grafts were placed over the two defects overlying the sclera.
CAG + CTG-P -A thin conjunctival layer was separated from one head of the pterygium.This layer was used to cover the defect overlying the sclera.The second defect was covered by a graft obtained from the superior conjunctiva.
During the postoperative period, the patients were put on steroids in tapering doses, antibiotics, and lubricants.During the postoperative visits, recurrence of pterygium was specifically looked for.

Results
A comprehensive analysis was conducted on 9219 eyes with pterygium.The eyes were categorized as follows: 8506 eyes in Group I, 385 eyes in Group II, 315 eyes in Group III, and 13 eyes in Group IV.The minimum period of follow-up was 12 months.The longest period of follow-up was 15 years.
In Group IV, 7.69% (1/13) of eyes showed recurrence.10% of eyes showed recurrence following split LCAG.Eyes that underwent CAG combined with SLET showed no signs of recurrence.

Discussion
The key objective of pterygium excision is to ensure minimal recurrence and good cosmetic outcomes.The most widely used method is conjunctival autografting.In our study, we aimed to formulate a treatment algorithm for different types of pterygium.
In double-headed pterygium, the conjunctival autograft can be split horizontally or vertically; with or without maintaining limbal orientation.All these methods were found to have good outcomes with low and comparable recurrence rates in our study.They also had cosmetically acceptable outcomes.
In some instances, especially with significant defects over the sclera defects, keeping the graft's orientation intact on the limbal side may not be feasible [7].We observed no notable variation in the recurrence rates of the different surgical techniques.
An earlier investigation at our institute on a different cohort followed the vertical split CAG method without preserving orientation on the limbal side [4].Only two eyes out of 95 developed recurrence (2.10%).Results from this study also demonstrate that this method is successful.
Other methods that can be used for double-head pterygium include Superior + inferior CAG, CTG-P, CAG + CTG-P, and AMG.We found that each method exhibited low recurrence rates, making them viable options.
Few authors studied the management of doubleheaded pterygium.Maheswari et al. reported no recurrence with the horizontal split CAG method [1].Elhamaky et al. reported no recurrence with the vertical split CAG method [8].The studies mentioned above were limited by their small study population.
Approaches for addressing recurrent pterygium encompass ER with LCAG/CAG, with/without MMC.Each method exhibited low recurrence rates, thus being a viable option.
The utilization of various adjuncts is beneficial in reducing recurrence [11].Complications associated with mitomycin-C include scleral melt, corneal melt, and punctate keratopathy [12].Difficulties related to amniotic membranes are their cost, storage, and availability.The literature also indicates a higher recurrence rate with this method [13].Grafts can be secured using either fibrin glue or sutures.Advantages of fibrin glue include ease of fixation, lesser operation time, and less postoperative discomfort.
A total of 9219 eyes with pterygium were included in our study.The recurrence rate was 0.47% in Group I, 3.63% in Group II, 2.86% in Group III and 7.69% in Group IV.Tables 2 and 3 show our study's outcomes compared to previous studies on double head and recurrent pterygium.The study's limitation lies in its retrospective nature, while its major strength is the substantial sample population and prolonged follow-up duration.As far as we know, this study is one of the largestscale assessments comparing the efficacy of various methods in addressing different types of pterygium.Based on our experience, the present study included, we have formulated a treatment algorithm for pterygium management (Fig. 2).

Conclusion
We mainly focused on comparing the recurrence rates in various surgical methods used in different types of pterygium in our study.All the methods we studied had a low recurrence rate.Based on our outcomes, a treatment algorithm was formulated for pterygium management.An extended follow-up period and a prospective study would give us more robust data on the effectiveness of the various methods.

Fig. 1
Fig. 1 Split CAG A. Adequately sized graft taken from superior conjunctiva; B. The graft was cut into two halves horizontally; C. Split grafts placed over the two defects; D. The superior conjunctival graft is vertically split into two halves; E. Limbal orientation is maintained; F. Graft may not completely cover bare area; G. Superior conjunctival graft is vertically divided into two halves; H.The limbal alignment is not upheld; I. Graft completely covers the bare area

Table 1 .
Comparison of different methods of pterygium excision in our study © 2024 The Authors.Romanian Journal of Ophthalmology

Table 2 .
Analyzing our results alongside existing studies on surgical management of double headed pterygium

Table 3 .
Our study versus other research on recurrent pterygium surgery